This invention relates to the separation of nonferrous metals such as aluminum, copper, zinc and brass and more particularly to the separation of aluminum particles from copper, zinc and brass particles. There are a number of known processes that take advantage of the different specific gravity of the materials to affect the separation of aluminum from the copper, zinc and brass. Fundamentally, density is a controlling factor in such gravity separating processes but it is more convenient to use the expression of density in the CGS system known as specific gravity. The metals of high density fall at a greater rate through a given fluid medium than those of lower density. A small dense particle may fall at the same rate as a larger but less dense particle, therefore attempts heretofore made to separate ores on the basis solely of their falling velocity in a given medium have not produced satisfactory results because of the many sizes of particles in any given material.